I was recently playing 
and multiple times in the game I pressed R and he started to ult but then the animation cancelled mid ultimate not going on CD. Multiple times i was in range I ulted and it just randomly stopped mid ultimate.
Birbonius1 votesDid it happen against enemies that didn't have any way of cancelling it? (Yasuo's wall,Yi's Q and such)
meowwow71 votesyas wall doesn't eat it that's what i love about naut ult
Birbonius1 votesThen it must've been bugged in one of my games,cause i remember it being cancelled by a yas wall one time,it was early too (we were both level 7 laning against each other) so there was nothing else.
yonggon1 votesno i was in range and everything ulting and it started ulting then just stopped mid ult and is swas against a kaisa
Professor Ward1 votesIt was being canceled, most likely facing a kaisa